Kim Sung-kyun is a South Korean actor. Kim began his career in theatre, then made his screen debut as a gangster boss's faithful henchman in Nameless Gangster: Rules of the Time (2012), followed by supporting roles in The Neighbor (2012), Reply 1994 (2013), Reply 1988 (2015–2016), Moon Lovers: Scarlet Heart Ryeo (2016), as well as leading role in series D.P. (2021–2023) and Divorce Attorney Shin (2023).

Nameless Gangster: Rules of the Time is a 2012 South Korean gangster film directed by Yoon Jong-bin starring Choi Min-sik and Ha Jung-woo. The film is set in the 1980s and ’90s in Busan when corruption and crime was so rampant that the government declared war on it in 1990.